Forage nutritive quality in the Serengeti ecosystem: The roles of fire and herbivory

American Naturalist
By: , and 



Fire and herbivory are important determinants of nutrient availability in savanna ecosystems. Fire and herbivory effects on the nutritive quality of savanna vegetation can occur directly, independent of changes in the plant community, or indirectly, via effects on the plant community. Indirect effects can be further subdivided into those occurring because of changes in plant species composition or plant abundance (i.e., quality versus quantity). We studied relationships between fire, herbivory, rainfall, soil fertility, and leaf nitrogen (N), phosphorus (P), and sodium (Na) at 30 sites inside and outside of Serengeti National Park. Using structural equation modeling, we asked whether fire and herbivory influences were largely direct or indirect and how their signs and strengths differed within the context of natural savanna processes. Herbivory was associated with enhanced leaf N and P through changes in plant biomass and community composition. Fire was associated with reduced leaf nutrient concentrations through changes in plant community composition. Additionally, fire had direct positive effects on Na and nonlinear direct effects on P that partially mitigated the indirect negative effects. Key mechanisms by which fire reduced plant nutritive quality were through reductions of Na-rich grasses and increased abundance of Themeda triandra, which had below-average leaf nutrients. ?? 2007 by The University of Chicago. All rights reserved.
Publication type Article
Publication Subtype Journal Article
Title Forage nutritive quality in the Serengeti ecosystem: The roles of fire and herbivory
Series title American Naturalist
DOI 10.1086/520120
Volume 170
Issue 3
Year Published 2007
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title American Naturalist
First page 343
Last page 357
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